1. Field of the Invention
This invention relates to negative component preceding zoom lenses, and, more particularly, to zoom lenses of a range beginning with a focal length equal to or shorter than the focal length of the standard lens for 35 mm single lens reflex cameras and a zoom ratio of 2:1 to 3:1 or thereabout.
2. Description of the Prior Art
There have been previous proposals for the 3-component zoom lens with the negative first, positive second and negative or positive third components, counting from the front; all of which are made to axially move in differential relation to each other to effect zooming, as, for example, disclosed in British Pat. No. 398,307, and Japanese Laid-Open Patent Applications Nos. SHO 54-26754, SHO 57-5023, and SHO 56-158316. These zoom lenses are amenable to a higher magnification range than that of the 2-component zoom lens of which the front is of negative power and the rear is of positive power, and, moreover, facilitate somewhat of a compact form. To achieve either a further reduction of the bulk and size of the entire system, or a much-desired increase in the widest angular field, however, the refractive power of each component must be strengthened with good stability of correction of all aberrations throughout the zooming and focusing ranges (when focusing is performed by the first component) being sacrificed. It has, therefore, been very difficult to realize a 3-component zoom lens of increased relative aperture and a higher grade imaging performance. Particularly with the first component having strengthened refractive power, variation of aberrations with focusing and zooming tends to increase. Also, with the second component having strengthened refractive power, variation of aberrations with zooming tends to increase.